jurnal tht fitri.docx
TRANSCRIPT
-
8/11/2019 JURNAL THT FITRI.docx
1/4
Abstract
Background: Many published epidemiologic studies confirm a marked increase in the prevalence of
asthma and allergic rhinitis. The link between allergic rhinitis and asthma has been extensively
studied and approximately 75% of patients with asthma have allergic rhinitis. The proportion of
patients with asthma in populations of allergic rhinitis patients has not been well studied.
Objective: The purpose of this study is to estimate the prevalence of undiagnosed asthma in a
specific population of patients presenting to an Otolaryngologist with symptoms of allergic rhinitis.
Study design: Prospective cohort study. Methods: Patients presenting with symptoms of allergic
rhinitis to two tertiary care Rhinology practices in Northern Alberta were asked to undergo allergy
skin testing, serum IgE quantification, and pulmonary functional testing. Patients with previous
asthma screening or known history of reactive airway disease or asthma were excluded.
Results: 107 patients with allergic rhinitis symptoms were recruited between September 2010 to
January 2013. Patients predominantly had perennial or persistent rhinitis (64.5%) with moderate-
severe symptoms (50.5%). While only 14.9% of patients had abnormal IgE levels, 68.8% had positiveskin testing. Abnormal pulmonary function tests were obtained in 39.1% of patients and 26.1% of
patients were diagnosed with asthma.
Conclusions: There is a high prevalence of undiagnosed asthma in patients presenting to tertiary
Rhinology care with moderate to severe allergic rhinitis symptoms. Screening lung function testing
should be considered in this patient population.
Introduction
Many published epidemiologic studies examining populations in Europe over the last few decadeshave confirmed a marked increase in the prevalence of asthma and allergic rhinitis [1-3]. One
recently published study estimates that the overall prevalence of allergic rhinitis in the Canadian
population is 20% with a high burden of disease, including limitations on lifestyle and poor symptom
control [4]. Similarly, overall prevalence of asthma remains high in Canada. Direct costs of managing
this chronic condition is increasing and it remains the number one cause of decreased productivity
and missed work days [5]. The link between allergic rhinitis and asthma has been extensively studied
[6]. Approximately 75% of patients with asthma have allergic rhinitis [7]. The proportion of patients
with asthma in populations of allergic rhinitis patients has not been well studied, with small studies
reporting ranges between 10 to 40% and no studies looking at this proportion in the Canadian
populations [7-9]. Studies have also shown that allergic rhinitis has a major impact on asthma
morbidity and that treating allergic rhinitis may also impact asthma control [10]. Several
explanations for this close relationship prevail in the literature. At the forefront is the unified airway
hypothesis, which states that both upper and lower airway allergic symptoms are manifestations of
the same atopic disease [11]. Asthma and rhinitis share many pathophysiologic characteristics [12]
and studies suggest that subclinical allergic inflammation is present in the lower airway of patients
with allergic rhinitis [13]. Clinically, both allergic rhinitis and asthma are triggered by many of the
same environmental allergens [14]. Furthermore, it is proposed that a loss of nasal function,
presence of a nasobronchial reflex, and propagation of inflammation from the upper to the lower
airways also contribute to combined nasal and airway inflammation
[15].The current understanding of shared pathophysiology between allergic rhinitis and asthma
prompted the World Health Organizations ARIA (Allergic Rhinitis and its Impact on Asthma) to
recommend asthma screening in patients with allergic rhinitis. Nonetheless, it is not current practiceby most Otolaryngology- Rhinology practitioners in Canada to order this screening routinely for
-
8/11/2019 JURNAL THT FITRI.docx
2/4
patients with symptoms consistent with allergic rhinitis. The purpose of this crosssectional study is
to estimate the prevalence of undiagnosed asthma in a specific population of patients presenting to
an Otolaryngologist with symptoms of allergic rhinitis.
Methods
University of Alberta Research Ethics Board approval was obtained prior to commencement of study
(Pro00032514).Adult patients (age 17 years of age) presenting to two Academic Otolaryngologists
with rhinology practices at the University of Alberta with one or more symptoms of rhinitis were
prospectively recruited between September 2010 and January 2013. Patients were diagnosed with
allergic rhinitis if at least one symptom of nasal itching, sneezing, nasal obstruction, congestion,
rhinorrhea, and/or hyposmia was present in association allergen exposure. Patients with
concomitant diagnosis of chronic rhinosinusitis with or without polyposis were not excluded.
Patients with known or previously diagnosed allergic asthma or reactive airway disease were
excluded. Severities of nasal symptoms were categorized as intermittent versus persistent and mild
versus moderate-severe in accordance with the WHO Allergic Rhinitis and its Impact on Asthma 2008Guidelines [http://www.whiar.org/Documents&Resources.php]. A four-point asthma-screening tool
was also administered to each patient (Table 1). Recruited patients subsequentlyn underwent skin-
prick specific IgE allergy testing, total serum IgE quantification, and pulmonaryfunction testing.
Diagnosis of asthma was based on demonstration of reversible airway obstruction with
bronchodilator administration as indicated by 12% increase in FVC (forced vital capacity) or FEV1
(forced expiratory volume in one second). Severity of asthma on pulmonary function testing was
classified by FEV1/FVC ratio according to standard ranges (http://www.ginasthma. org/). All data
recorded were compared to norms based on age, gender, race, weight and height. All patients
underwent testing at the same diagnostic laboratory. Results of testing were prospectively collected
in a database.
Risk factor analysis
SPSS 20.0 was used for statistical analysis. Factors were examined for association with increased
likelihood of asthma using Mantel-Haenszel tests followed by regression analysis using likelihood
ratio tests. A significance level of p < 0.05 was used for all analysis.
Results
One hundred and seven patients were recruited during the study period (Figure 1 and Table 1). The
majority of patients had persistent and moderate-severe symptoms of allergic rhinitis (Table 1) and
17.8% of patients had clinical and/or radiographic evidence of chronic rhinosinusitis with or without
polyposis.Almost 87% of patients responded yes to two or more questions from the Asthma
Screening Tool (Figure 2).
IgE-allergy skin testing
68.8% of patients had positive IgE-specific skin testing (Table 2). On average, patients were
sensitized to 3.5 allergens (Range 1 to 20). 20.0% of patients had negative skin-prick testing despite a
history of environmental allergies.
http://www.ginasthma/http://www.ginasthma/http://www.ginasthma/http://www.ginasthma/ -
8/11/2019 JURNAL THT FITRI.docx
3/4
Pulmonary function testing
92 patients underwent pulmonary function testing with abnormalities found in 36 patients (39.1%).
Of the abnormal results, 24 patients had a diagnosis of asthma (26.1%) based on diagnostic criteria
outlined in Methods. The distribution of severity of asthma is shown in Table 3.
Risk factor analysis
Regression analysis failed to show any independent risk factors for increased risk of asthma
diagnosis (Table 4).
Discussion
This study found a high rate of undiagnosed asthma in a population of patients with allergic rhinitis
presenting to tertiary care Rhinology in Northern Alberta. The results of this study support the
existing evidence for a strong association between asthma and allergic rhinitis. It also supports
studies that have demonstrated AR as an independent risk factor for asthma [7]. To our knowledge,
there are currently no other studies in the literature that examine the rate of undiagnosed asthma in
allergic rhinitis patients. Also, no studies have examined, specifically, the value of asthma screening
in this population despite recent ARIA guidelines, which recommended that persistent allergic
rhinitis should be evaluated for asthma [16]. We found that 26.1% of patients in our cohort had
asthma on pulmonary function testing. Majority of patients in our cohort were subsequently
referred to Pulmonary Medicine for further management of their lowerairway disease. Although not
all patients required immediate initiation of medical management, earlier detection of asthma
potentially facilitates patient counseling and long-term management of their disease. In addition,
substantial literature exists that demonstrate benefits of managing AR in patients with co-morbid
asthma [17]. Our study failed to identify any specific risk factors for abnormal pulmonary function
test results in patients with allergic rhinitis. Specifically, a family history of atopy, positive allergy skin
testing and answers to the 4- point allergy-screening tool failed to predict likelihood of asthma.
Some authors have suggested that a serum IgE level > 140 IU/ml may be predictive of atopic disease
[18], while others have suggested lower limits or even limited utility [19, 20]. At our institution, a
total IgE of greater than 120 IU/mL is considered abnormal, but this finding in our patients, while
yielding an Odds Ratio of 2.667 with findings of asthma on PFT, failed to reach statistical significance.
Further studies are necessary to examine other potential risk factors for increased likelihood asthma
in AR patients such as duration of allergic rhinitis, geography, and respiratory sensitizer exposure.
Admittedly, this is a cross-sectional study with a relatively small sampling of patients in Alberta and
is highly selected the patients in our study had significant nasal complaints as demonstrated by a
high proportion of patients with moderate-severe (50.5%) and persistent rhinitis (64.5%). This is in
contrast to the mild symptoms seen in the general population who are likely managed by primary
-
8/11/2019 JURNAL THT FITRI.docx
4/4
care practitioners [21]. In addition, the study patients would benefit from observation for longer
periods of time. It is possible that patients with initially normal PFTs may subsequently develop
evidence of lower airway disease if followed over time. Finally, the overall prevalence of asthma in
Canada varies between 5 and 10%, with Alberta reporting the highest rates in Canada of up to 10.2%
[22, 23]. Thus, the results of our study may not be applicable to other regions. Similar studies from
other centers in Canada would help clarify this question. Despite these limitations, the results of thisstudy remain useful to clinicians that treat patients with a spectrum of AR severity. It reinforces the
fact that AR is not a trivial disease and should be managed aggressively to optimize progression of
airway reactivity. In patients with persistent and severe disease, there is a high rate of undiagnosed,
but clinically significant asthma and we feel this warrants consideration for increased asthma
screening by practitioners who see allergic rhinitis patients. Future studies examining the cost-
effectiveness of asthma screening in this population are necessary before widespread adoption.
Conclusions
There is a high prevalence of undiagnosed asthma in patients presenting to tertiary Rhinology carewith moderate to severe allergic rhinitis symptoms. Screening lung function testing may be
considered in this patient population.
Competing interests
The authors declare that they have no competing interests. Authors contributions DWJC, EDW, MB,
and HV conceived and designed the study. DWJC, EDW, MB, HV, and CCJ collected the study data.
CCJ analyzed the data and prepared the manuscript. DWJC, EDW, MB, HV, HS, and CCJ approved the
final manuscript.
Author details
1. Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of
Alberta, 8440 112 Street, Edmonton, Alberta T6G 2B7, Canada.
2. Division of Pulmonary Medicine, Department of Medicine, University of Alberta, 8440 112
Street, Edmonton, Alberta T6G 2B7, Canada.
Received: 3 April 2013 Accepted: 3 September 2013
Published: 19 December 2013